Two cDNA libraries containing genes expressed specifically in rat hippocampus and rat cerebral cortex will be generated. Individual clones will be analyzed by Northern blotting and selected clones will be sequenced. This will yield statistical information on the genetic relationship between these evolutionary and phylogenetically contrasting brain structures. It will also provide the sequences of hippocampus and cortex-specific mRNAs. Using the genetic code, the protein sequence will be determined for each open reading frame. Synthetic peptides will be produced which match selected regions of each hippocampus or cerebral cortex-specific protein and these will be used to immunize rabbits. The resulting antipeptide antisera will be used in a number of immunocytochemistry experiments to probe brain slices using light and electron microscopy. This will provide anatomic information and suggest a functional role for each novel region-specific protein. Tissues to be probed include adult rat brain, developing rat brain, and human brain from Alzheimer's disease patients, schizophrenics and temporal lobe epileptics.